Magnetic random access memory or MRAM is a nonvolatile random access memory technology. When MRAM is used as an off-chip cache, there is a security risk due to the MRAM being nonvolatile.
For instance, since the MRAM retains its data after being powered off, someone could walk off with a board, power it on, and read all the data in the MRAM. The MRAM is naturally nonvolatile, so there is no way to design it to be volatile.
Thus, techniques for preventing data retrieval from nonvolatile memory, such as MRAM, when used as an off-chip cache would be desirable.